Disk drives typically use heads residing on sliders to read from and write to the magnetic media. Read and write transducers residing in the head are flown at a small, controlled spacing above the magnetic medium during read and write operations. To determine the controlled spacing, it is desirable for the disk drive to detect at what point the head contacts the media, known as a touchdown event.
For example, heads typically use a thermal actuator that generates heat to control the head-media spacing. Heat generated by the thermal actuator causes local thermal expansion of the head, which locally reduces the spacing between the head and magnetic media. The thermal actuator can be driven to induce sufficient heating for contact between the head and media. This touchdown is intentional and may be performed on each drive during initial drive calibration.
Touchdown may be detected in the drive operation as well as in testing. Conventional touchdown detection may be performed using a variety of techniques. For example, touchdown may be detected through disk slow down, readout channel noise, strain gauges, PES variations, and/or acoustic emission.
Accordingly, what is needed is a system and method for providing improved touchdown detection.